PESHAWAR, Pakistan  Truckers who carry supplies to NATO troops in Afghanistan went on strike in northwest Pakistan to protest lower pay, inadequate security and corrupt officials who demand bribes from the truckers, officials said.

The supply route is an important lifeline for international forces in landlocked Afghanistan. The coalition ships about a significant portion of its nonlethal supplies through Pakistan into southern Afghanistan. The other land route into Afghanistan through Central Asia and Russia is longer and more expensive.

The strike began Wednesday in response to the government’s decision to require truckers to go through authorized companies to carry NATO supplies instead of making individual deals with the government-run National Logistics Cell, said Jehanzeb Khan, head of a transport workers union in northwest Pakistan. The companies pay the truckers less, said Khan.

He also claimed the government was not providing adequate protection to the drivers from Taliban attacks, and each truck had to pay corrupt security officials about $165 in bribes to pass through the Khyber tribal area on the way to the border.

Khan said truckers in northwest Pakistan have stopped carrying NATO supplies, and he was reaching out to others throughout the country to get them to join the strike.

No trucks carrying NATO supplies crossed the northwest Torkham border on Wednesday, said local political official Tahir Khan.

Torkham is one of two crossings used to ship NATO supplies to Afghanistan.